A new Omnimax Show "Sea Monsters: A Prehistoric Adventure" will be screened at the Hong Kong Space Museum from Monday (March 1) until August 30.

The film will bring vividly to life the bizarre, ferocious and fascinating ocean creatures that lived 80 million years ago. The film will not only take audiences on a remarkable visual journey, but also enable them to trace circumstantial evidence to study paleontology.

"Sea Monsters: A Prehistoric Adventure" is the story of a family of Dolichorhynchops (also known informally as "Dollies") as they traverse ancient waters populated with sabre-toothed fish, prehistoric sharks and giant squids. On their journey the Dollies encounter other extraordinary sea creatures: lizard-like reptiles called Platecarpus that swallowed their prey whole like snakes; Styxosaurus with necks more than six metres long and paddle-like fins as large as an adult human; and on the top of the food chain, the monstrous Tylosaurus, a predator with no enemies.

Eighty million years ago, many places on Earth were undersea. For example, today's Kansas, in the central United States, was at the bottom of a great inland sea dividing the then North America into two. A warmer climate meant more of the globe was submerged. Europe was just a smattering of islands, much of Asia was underwater and a shallow ocean engulfed nearly all of Australia at that time. On this sodden sphere, seagoing reptiles flourished, and after these ocean giants died, their skeletons became fossils and were left in locations that are now high and dry.

The first reptiles lived on land, as did the ancestors of the living crocodiles, lizards and snakes. These proto-reptiles were small and light-boned, not unlike most lizards today. This was probably because smaller bodies were easier to maintain on the insects that could be found on the floor of the Carboniferous forests, and heat up in whatever sunlight managed to break through the canopy of trees.

Reptiles dispersed to various terrestrial habitats, and some moved to the sea. In geological time, this turnaround occurred soon after conquest of the land almost 300 million years ago (the Permian). Mesosaurus, the known first marine reptile, was a one-metre-long, fully aquatic lizard-like animal that propelled itself underwater with its elongated tail and webbed hind limbs.

While the terrestrial dinosaurs had legs, the marine reptiles had flippers and other appropriate skeletal modifications for the marine environment and their aquatic existence. After the mesosaurs, the next earliest marine reptiles were the nothosaurs, which had slender bodies, long necks and tails, and webbed limbs. The process of turning a Permian scaly reptile to a fully armoured creature with flippers for feet is unclear. The marine reptiles also developed skull modifications that would serve them well for moving through the water and capturing their prey. The skulls of most of the marine reptiles were flattened or tapered to reduce water resistance. Regardless of how well adapted they seemed for a marine lifestyle, they all had to come to the surface to breathe.

While living birds are now considered the lineal descendants of dinosaurs, the sea monsters that had gone for 65 million years left no offspring. People who want to learn more about these prehistoric ocean creatures should not miss "Sea Monsters: A Prehistoric Adventure".

The 40-minute Omnimax Show, "Sea Monsters: A Prehistoric Adventure", will be screened at 1.30pm, 5pm and 8.30pm daily at the museum's Stanley Ho Space Theatre. The museum is closed on Tuesdays (except public holidays). Tickets are available at the Space Museum Box Office and at all URBTIX outlets for $24 (front stalls) and $32 (stalls). Full-time students, senior citizens aged 60 or above and people with disabilities will receive a half-price concession.

The Space Museum is located at 10 Salisbury Road, Tsim Sha Tsui, Kowloon. For further information, call 2721 0226 or visit the website http://hk.space.museum .